Weeelllll, the DIS transportation site, much to my personal chagrin, does, in fact, say that DME's service is at limited resorts..unless you read it very carefully anyway. The site barely differentiates between RAC and DME..so it's easy to see how someone could be confused.
And even then, if you do discern that it's talking about RAC, it still says that SW is available at 'limited resorts', which is wrong.
So...long story short...
Anyone arriving at MCO, on any airline, or by car, or by yak, and that has a standing DME reservation (made in advance) is entitled to ride the DME bus to their resort from the airport. If you have tagged your checked bags, you can expect those bags to show up, in your resort room, up to 3 hrs after resort checkin. Unless....you arrived at the airport between 10pm and 5am. Baggage handling is suspended after 10pm..so you will need to get your own bags and take them on the bus with you. I would not tag the bags in this case.
For your return to the airport??? Again, every guest with a standing reservation with DME is entitled to ride it back to the MCO from their resort. you are allowed to bring all your luggage, checked and carryon, with you, on the bus.
If you are flying on one of the participating airlines, and your flight is after 8:15am, you can check your bags right at the resort and get your boarding passes issued. You do NOT need to have a prior reservation on DME for this...you can even check your bags with RAC and then take a car service back to the airport, or a rental car. You just have to be flying out on a 'participating airline'.